To howls of laughter, Ms Margolyes told the crowd at Canberra's Commonwealth Park that she came to Australia because, ''I fell in love with an Australian … woman, by the way, in case anyone didn't know I'm a dyke - and I'm very happy.''

''And I am proud to be one of those 4 million,'' she said. ''As migrants, we did not just adopt a new country. We helped transform and enrich it. And together, as new Australians and old, we made this experiment work.''

In Adelaide, Opposition Leader Tony Abbott offered a message of empathy to those feeling anxious about change.

Mr Abbott said it should be in accordance with Australia's customs and traditions.

''Sometimes, those of us who have been here for a long time get a little bit anxious about the changes that are taking place in our country,'' Mr Abbott told an Australia Day breakfast and citizenship ceremony.

''It should be change in accordance with the customs and traditions of our people.''

Mr Abbott said he cherished the cultural diversity of Australia.

''Above all else I cherish our unity,'' he added.

''And by looking to become Australian citizens, you are celebrating that which we have in common.''